When many organic chemical liquid compositions, such as hydrocarbon fuels or similar materials, are loaded from a loading facility or system into the tanks or holds of shipping vessels, significant quantities of volatile organic compounds may be released. The vapor released may not only be environmentally polluting but, in sufficient amounts, may present a dangerous fire or explosion hazard. To overcome these concerns, elaborate vapor control schemes and systems have been incorporated over the years into loading operations and systems for capturing the vapor released during loading.
In many instances, the vapor control systems were designed or sized to handle volumes of released vapor based on expected volumes of the fuels, etc., to be loaded, the expected volumes being, in turn, based on best estimates of future demand. However, a combination of unexpected increased consumer demand and increasingly stringent governmental environmental regulations are causing many existing vapor control systems to run near capacity.
With demand for these materials expected to increase to even greater levels, it is evident that existing vapor control systems will be unable to process the volumes of volatile component(s) at a regulatorily required level. While new systems may be installed, or existing vapor control systems may be expanded, significant capital costs are involved. In addition, until the new or expanded systems are operational, loading operations will be restricted by the limited capacity of the current systems. Accordingly, there has been a need for an approach for handling increased loading volumes which avoids the costs and limitations mentioned. The invention addresses this need, and, in a preferred aspect, is directed to loading operations, apparatus, and systems for loading organic chemical liquids, particularly various grades of gasoline, diesel and other distillates, and compositions referred to generally as petroleum hydrocarbons.
The invention proceeds from an evaluation of the operations of the loading terminal or system, including the spectrum of liquid compositions to be loaded, and from the discovery that circumstances may allow, during loading of some liquid compositions in a vessel, non-use or bypass of the vapor control system or unit. More particularly, some organic chemical liquids to be loaded are of such limited volatility that release or venting of the very minor quantities of vapors released from the vessel during loading will be minimally or essentially non-polluting and the loading operation will therefore remain in compliance with governmental environmental regulations. As employed herein, the expression xe2x80x9cliquid of limited volatilityxe2x80x9d refers to an organic chemical liquid, including mixtures thereof, having such limited vapor pressure that its handling in the environment, such as in a loading operation, does not generate a quantity of vapor or vapors sufficient to exceed governmental environmental regulations or standards. In normal loading operations, such as at a refinery or chemical plant, the vapor pressure of an organic chemical liquid to be loaded will either be known, or may be determined by routine testing, so that a comparison of the particular liquid""s true vapor pressure at standard conditions with published governmental environmental limits, which may vary from time to time, may readily be made and the liquid""s suitability for venting of vapor determined. At the present time, an organic chemical liquid having a true vapor of below 1.5 psia at 60xc2x0 F. would meet such governmental requirements.
Broadly, therefore, the invention relates to a novel procedure, apparatus, and system for loading organic chemical liquids in a transporting vessel. In addition, a vapor control logic system is provided which controls flow direction of vapor captured from a transporting vessel being loaded, either to a vapor control system or to vent in response to user input or inputs. Accordingly, in one aspect of the invention, there is input into an input or input means of the logic system mentioned the nature of the organic chemical liquid to be loaded and, if the liquid is a liquid of limited volatility, a further user determination input of whether or not the previous load in the vessel was a liquid of limited volatility. A processor, coupled to said user input or inputs, and responsive thereto, being configured to process one or both of said input determinations, outputs directions for control or disposition of vapor captured or collected while loading the vessel, as described more fully hereinafter.
Alternatively, the vapor control logic system may be designed to input first the user determination of whether or not the previous load in the vessel was a liquid of limited volatility, and, if the previous load was a liquid of limited volatility, a user determination input of the nature of the organic chemical liquid to be loaded in the vessel. In a similar manner, the processor, coupled to said user input or inputs and responsive thereto, and appropriately configured to process one or both of said input determinations, outputs directions for control of vapor captured, as also described more fully hereinafter.
In both cases, the processor, which will be a computer, will be programmed or configured to output directions, as follows. If a load to be loaded is a volatile organic chemical liquid, or if the previous load of the vessel was not a liquid of limited volatility, the flow of captured vapor will be directed to the vapor control system or unit. If the load to be loaded is a liquid of limited volatility, but the previous load was not, the captured vapor will be sent to the vapor control system. However, if the load to be loaded is a liquid of limited volatility, and the previous load of the vehicle was a liquid of limited volatility, the flow of captured vapor(s) will be diverted from the vapor control system and directed to means for venting to atmosphere. If it is not known or ascertainable if the previous load of the vehicle was a liquid of limited volatility, the flow of captured vapors is directed to the vapor control unit. As a failsafe in either case mentioned, the system may further provide optional means for analyzing the captured vapors, as described hereinafter, for preventing an inappropriate atmospheric release.
In a preferred embodiment of the invention, there is input into the logic system the nature of the organic chemical liquid to be loaded and, if a distillate, whether or not the load previously carried by the vessel was a distillate composition. As utilized herein, the expressions xe2x80x9cdistillatexe2x80x9d and xe2x80x9cdistillate compositionxe2x80x9d, or plural variants thereof, are understood to refer to liquid of limited volatility which is refined from petroleum, and comprising refined hydrocarbon mixtures having a true vapor pressure of below 1.5 psia at 60xc2x0 F. As will be understood by those skilled in the art, some compounds or components present in such hydrocarbon mixtures are not composed solely of carbon and hydrogen, but may contain other elements, such as nitrogen, oxygen, and sulfur. Common distillates include diesel, oils, such as #1 and #2 fuel oils, kerosene, home heating fuel oil, high sulfur fuel oil, and similar liquids.
In this preferred embodiment, the processor processes the input, and controls the flow of captured or vapor or vapors, as described. If the load to be loaded is not a distillate, e.g., is gasoline, or if the previous load of the vehicle was not a distillate, the flow of captured vapor will be directed to the vapor control unit. If the load to be loaded is a distillate and the previous load of the vehicle was a distillate, the very minimal flow of captured or collected vapor will be diverted from the vapor control system and directed for venting to atmosphere. If it is not known or ascertainable if the previous load of the vehicle was a distillate, the flow of released vapors is directed to the vapor control unit. As already mentioned, as a failsafe, the system may provide optional means for analyzing the captured vapors, as described hereinafter, for preventing inappropriate atmospheric release.
The invention further includes a logic system for controlling vapor released and captured while loading a vessel. The system comprises a) a user input or input means for receiving a user determination input of the nature of an organic chemical liquid to be loaded in a vessel, and, if the liquid to be loaded is of limited volatility, a user determination input of whether or not the previous load in the vessel was a liquid of limited volatility; and b) a processor, coupled to said user input and responsive thereto, being configured to process one or both of said input determinations and output directions for control or disposition of vapor captured or collected during loading. As will be understood, the user input or input means may alternately comprise an input for receiving a user determination input of whether or not the previous load in the vessel was a liquid of limited volatility, and, if the previous load was a liquid of limited volatility, a user determination input of the nature of an organic chemical liquid to be loaded in a vessel.
The invention further comprises apparatus for controlling vapors released while loading a vessel which includes the vapor control logic system embodiments described, and further includes means for capturing vapors released during loading, and means coupled to and controlled by the processor for directing the captured vapors to a vapor control system or to vent.
In a most preferred aspect, the invention comprises a method of loading of a vessel from a loading system including a vapor control system comprising providing a vapor control logic system which controls flow direction of vapor captured from a transporting vessel being loaded to a vapor control system or to vent; inputting into the logic system the nature of the organic chemical liquid to be loaded and, if a distillate, whether or not the load previously carried by the vessel was a distillate composition; processing the inputs in the vapor control logic system; loading the vessel and capturing vapor released from the vessel during loading; and controlling the flow of the captured vapor in response to the inputs to the logic system, either to the vapor control system or to vent. As suggested previously, the inputs will be processed by the processor in the following manner. If an input to the logic system is that liquid to be loaded is a volatile organic chemical liquid, e.g., gasoline, the flow of captured or collected vapors is directed to the vapor control system. If an input to the logic system is that the previous liquid loaded in the vessel was not a distillate, the flow of captured vapors is also directed to the vapor control system. If the inputs to the logic system are that the load to be delivered is a distillate, but the previous liquid loaded in the vessel was not a distillate, the flow of captured vapors is directed to the vapor control system. However, if the inputs to the logic system are that the load to be delivered is a distillate, and the previous load of the vessel was a distillate, the flow of captured vapors may be diverted from the vapor control system and vented to atmosphere. This aspect of the invention also permits the alternative first user determination input of whether or not the previous load in the vessel was a liquid of limited volatility.
In yet a further embodiment, the invention relates to a loading terminal for selective recovery of volatile organic compositions released during the loading of a transporting vessel from a loading system including a vapor control system. The terminal includes means for loading a vessel, and a vapor control system for processing vapors released during loading. According to the invention, means are further provided for capture and selective transfer of vapor released during loading to the vapor control unit or to vent, the means for capture and transfer including programmed computer processing means, for controlling flow of captured vapor, in response to user determined input or inputs. Preferably, the logic control system mentioned may be provided, with access by a user by appropriate means, and means for input or inputs of information to be processed. The terminal provides means for processing the inputs, with outputs for control of captured vapor, by appropriate means, to the vapor control system or to means for vent.